Comment Re:Their own technology? (Score 5, Informative) 130
Look up Amazon Aurora.
They've basically created new a DBMS that runs on top of their cloud infrastructure and is optimized for their EBS (elastic block storage). They have Postgres and MySQL flavors of the database, both of which utilize the actual DB "engines", Amazon has written their own storage backends and added a bunch of other optimizations to the codebase (they've made most messaging asynchronous where possible). Because of the use of the actual database engines they claim 100% compatibility for both Postgres and MySQL. We use the MySQL flavor and haven't run into any compatibility issues with SQL queries or stored procs. Because of the performance optimizations inherent in how it was designed to run in their cloud, we were able to significantly reduce the amount of CPU/RAM utilized to run our application and still retain similar throughput - in essence, we were able to use a smaller RDS instance size, thus reducing our costs.
One of the really nice things about it is virtually instant (and faultless) replication due to the way they rely on EBS itself to replicate data, rather than through a replication system sending queries (or binary data) to another remote system.